A pure culture of S. mutans at steady stae in a continuous culture (chemostat) was pulsed with a mixture containing sodium fluoride and 14C labeled glucose. The pulse was applied to steady state populations at a low and high growth rate for pH values of 7.0, 6.2 and 5.4. Samples were obtained before the pulse and at timed intervals after the pulse. The samples have been analyzed for fluoride, residual glucose, 14C label incorporation, dry weight, ATP, lactic acid and volatile fermentation products.